Unidirectional fiber materials are used in ballistic-resistant structures and are disclosed, e.g., in U.S. Pat. Nos. 4,916,000; 4,079,161; 4,309,487 and 4,213,812. A non-woven ballistic-resistant laminate is disclosed in U.S. patent application Ser. No. 11/986,624 filed in the names of Ronald G. Krueger, Ronald L. Krueger, and Chris A. Yancy on Nov. 21, 2007, the complete disclosure of which is incorporated herein by reference. The laminate structure is used in soft body armor to protect the wearer against high-velocity bullets and fragments. The non-woven ballistic-resistant laminate is made by first forming a non-woven unidirectional tape, which is composed of a bundle of unidirectional polyethylene or other high strength filaments fibers and an elastic resin material that holds the fibers together. A layer, or array, of the unidirectionally-oriented bundles of high strength filaments is then laminated together between polyethylene, polypropylene or other thermoplastic films to form the ballistic-resistant laminate assembly or panel. The thermoplastic film retains the filament bundles in the array. The film also prevents adjacent panels from sticking together when the panels are layered in the soft body armor. The individual ballistic-resistant panels are layered in a cross-plied manner, with alternate panels having their arrays of filament bundles crosswise to those of adjacent panels, to meet structural requirements of ballistic-resistant body armor, such as impact force distribution.
However, known ballistic-resistant laminates are limited in their ability to provide a satisfactory light weight and flexible ballistic-resistant body armor structure.
U.S. Pat. No. 5,173,138, issued Dec. 22, 1992, the complete disclosure of which is incorporated herein by reference, teaches a method and apparatus for the automated production of a cross-plied material, preferably for structural or anti-ballistics end use. Here, the plies comprise unidirectional fibers in a resin system and carrier webs of release paper. The apparatus includes means for advancing a first, continuous ply of material into a cross-plying zone; means for sequentially laying a plurality of discontinuous second plies of material coplanarly on the first ply in the cross-plying zone with the longitudinal axis of each of the second plies rotated relative to the longitudinal axis of the first ply; means for preconsolidating the continuous first and consecutive second plies; and means for withdrawing the cross-piled material from the cross-plying zone. The method features the steps of advancing the first ply of material into a cross-plying zone; sequentially laying the second plies of material coplanarly on the first ply in the cross-plying zone with the longitudinal axis of each of the second plies rotated relative to the longitudinal axis of the first ply; preconsolidating the first and the second plies; withdrawing the cross-piled material from the cross-plying zone; and separating the cross-plied material from the carrier webs. The cross-piled material produced can be rolled up in a bolt with a polyethylene or other interleaf film that functions as a release boundary layer to the cross-plied material, for subsequent processing or use.
The present invention method and apparatus for the automated production of a cross-plied material that achieves greater flexibility than material manufactured according to the teachings of U.S. Pat. No. 5,173,138.